A luminaire of the type as described in the opening paragraph is known from EP2634474A1. It is a known problem with these types of luminaries that a relatively large thickness, i.e. a relatively high sidewall, is required, for example, because of the space required to accommodate luminaire components such as voluminous, acoustic material, light sources, wiring, electronics, heat sinks etc. Often these luminaires are applied as pendant luminaires and thereto are suspended from the ceiling to give the impression of a floating luminaire usually to illuminate office desks and conference tables for people to work. However, due to the large width, or height or thickness of the sidewall of these pendant luminaries, the issue arises that people working below these pendant luminaires feel uncomfortable because of the impression of rather heavy and thick luminaires being suspended over their heads. The known luminaire solves this issue by positioning luminaire components of relatively large height at a central region of the first and second main face, i.e. remote from the sidewall. The housing then being thick in its central region and being slim in a peripheral region, i.e. close to the sidewall. However, this solution involves the disadvantages of elongated wiring and relatively little room being available for the accommodation of luminaire components with the subsequent risk on early failure of electronic components because heat generating or heat dissipating component, for example heat sinks, and heat sensitive electrical components are positioned relatively close to each other.
DE102012205188A1 discloses a luminaire having a light exit window in a first main face and a light emission window in a sidewall which both are associated with the same light source.